For many decades small internal combustion engines, such as those used for motor vehicles, recreational vehicles and lawn and garden tools like chain saws, trimmers, tractors, and lawn mowers, have typically used diaphragm carburetors to regulate the air-fuel mixture supplied to the internal combustion engine. Typically diaphragm carburetors have a main body with an air-fuel mixing passage adapted for fluid communication with a fuel metering chamber assembly, which in turn is in fluid communication with a fuel pump chamber. The fuel metering chamber assembly is typically constructed from separate bodies attached to one another with a diaphragm carried between the separate bodies. The fuel metering chamber assembly provides a regulated supply of liquid fuel to the air-fuel mixing passage, typically through a fuel nozzle having a relatively small diameter fuel passage. The fuel passage of the fuel nozzle typically terminates within the air-fuel mixing passage and in rotary throttle valve connectors is commonly adapted for close receipt of a needle valve. The needle valve typically moves relative to the fuel nozzle to regulate, at least in part, the amount of liquid fuel flowing through the fuel nozzle into the air-fuel mixing chamber.
Unfortunately, in use, the fuel passage of the fuel nozzle commonly gets clogged, at least partially, with dirt, dust, or the like. When the fuel passage becomes clogged, the running performance and efficiency of the engine declines, and unless the fuel nozzle is cleaned, the engine can stop running altogether. Accordingly, the fuel nozzle, and/or other components of the carburetor, typically require periodic cleaning.
Cleaning diaphragm carburetors can prove challenging. Typically, to clean the fuel nozzle, the fuel metering chamber assembly needs to be disassembled from the air-fuel mixing body. While disassembling the fuel metering chamber assembly, the upper and lower bodies of the assembly are typically able to separate from one another, thereby exposing the diaphragm between the bodies to potential contamination and damage. Accordingly, while attempting to clean the fuel nozzle, typically three separate bodies can separate from one another, thereby increasing the potential for further contamination. Thus, efforts to clean the fuel nozzle are generally complicated, labor intensive and can result in additional contamination of the carburetor.